New to the list, I have a 97 Explorer Sport 4.0 SOHC. I usually get 16 mpg avg and 19 tops, but on a recent trip I tried driving slower, set the cruise to 67 and got 22.5 mpg. Wow! It pays to slow the brick down. I was also wondering about installing taller gears, like a 3.25 or 3.45 set. I...